As humans age, physical, environmental, and medical conditions affect the quality and appearance of skin. Wrinkles are the most common skin condition associated with physical aging. Dermatologists and plastic surgeons describe two types of wrinkles—static and dynamic. Static wrinkles are wrinkles associated with advancing age; they are caused by the thinning and stretching of the skin over time and are always visible, regardless of whether the facial muscles are active or resting. Dynamic wrinkles are not associated with the aging process; they are temporary wrinkles caused by the creasing of skin and are visible only when the facial muscles are active. Other skin conditions associated with aging are dry skin and liver spots. In addition to aging, dietary swings are another physical condition that affects the quality and appearance of skin. With the stretching of the skin during periods of weight gain and the relaxation of the skin during periods of weight loss, the skin loses its elasticity.
Environmental conditions that affect the skin include exposure to the sun and tobacco smoke. Overexposure to sunlight results in photodamage (also called photoaging), a condition that affects both the epidermal and dermal layers of the skin. Specifically, in the epidermis, photodamage results in the thinning of the epidermal layer of the skin and may also cause the growth of skin lesions, such as actinic keratoses, basal cell carcinomas, and squamous cell carcinomas. In the dermis, photodamage results in an accelerated rate of collagen degeneration resulting in premature aging. With the destruction of the collagen fibers in the dermal layer, sun-induced elastin accumulates in the skin producing large quantities of metalloproteinase enzymes. Normally, metalloproteinases remodel sun-injured skin by manufacturing and reforming collagen; this process does not always work well to repair damaged skin as some metalloproteinases may actually break down collagen. The result of this imperfect repair process is the formation of disorganized collagen fibers known as solar scars. With prolonged and continuous sun exposure, the imperfect rebuilding of the skin by this process results in wrinkles. Exposure to tobacco also has a detrimental effect on the condition of the skin. It has been found that the chemicals inhaled form cigarette smoke constrict the blood vessels in the skin resulting in a diminished flow of oxygen to facial tissues. The reduced flow of oxygen to the facial skin of smokers may result in premature wrinkling and a grayish pallor.
Medical conditions that affect the skin are widespread and include such conditions as acne, acne scarring, rosacea, psoriasis, and eczema. Despite years of research and a myriad of products designed to address these common skin disorders, they remain common conditions that are difficult to cure or to control.
Compositions including vitamins A and E have been touted as effective for the treatment of skin conditions and the reduction in the appearance of wrinkles. The term vitamin A is the generic term to describe the class of fat-soluble compounds known as retinols. The retinols, one of the most active forms of vitamin A, are found in animal foods such as liver and eggs. Retinols, however, are not the only source of vitamin A; the provitamin A carotenoids (also called “carotenoids”) found in the darkly colored pigments of some plant foods convert to vitamin A within the body and are thus, another source of vitamin A. The carotenoids are defined by their chemical structure. The majority of carotenoids are derived from a 40-carbon polyene chain, which could be considered the backbone of the molecule. The polyene chain may be terminated by cyclic end-groups and may be complemented with oxygen-containing functional groups. Hydrocarbon carotenoids are known as carotenes. Some common carotenes include beta-carotene, found in carrots; alpha-carotene, found in palm oil; beta-cryptoxanthin, found in red bell peppers and citrus fruits; and lypocene, found primarily in tomatoes. The structure of a particular carotenoid determines the biological function of the pigment. For example, the distinctive pattern of alternating single and double bonds in the polyene backbone of the carotenoids is what allows the compounds to absorb excess energy from other molecules, while the nature of the specific end groups on the carotenoids influences the polarity of the compound. The former may account for the antioxidant properties of biological carotenoids, while the latter may explain the differences in the ways that individual carotenoids interact with biological membranes. Vitamin A and carotenoids play an important role in vision, bone growth, reproduction, cell division, and cell differentiation. These compounds helps to maintain the integrity of skin and mucous membranes and thus, it helps to protect the skin from elements that damage the skin, such as the environmental factors described above, as well as bacteria and viruses, which are the causes of many medical skin conditions, such as those described above. Despite its beneficial effects, the carotenoids have not been successfully used in topical formulations because the pigments of these compounds produce severe skin discoloration.
The term vitamin E is the generic term to describe the class of fat-soluble compounds known as tocols and tocotrienols. The term “tocopherol” is a generic descriptor for all mono-, di-, and trimethyltocols. Alpha-tocopherol is one of the most active tocopherols; it is found in vegetable oils, nuts, and green leafy vegetables. Tocotrienols differ from tocopherols in that the former have an unsaturated isoprenoid side chain. Palm oil is the richest natural source of tocotrienols, and unlike tocopherol, is not found in most of the other vegetable oils such as soybean oil, canola oil, corn oil, and cottonseed oil. Within palm oil, tocotrienols make up about 70% of the total vitamin E in the oil while tocopherols make up only 30% of the total vitamin E in the oil. Both tocopherols and tocotrienols have been found to be powerful biological antioxidant in humans. Antioxidants act to protect cells against the effects of free radicals—those potentially damaging by-products of the body's metabolism that can cause cellular damage. In addition to its anti-oxidant properties, the tocotrienols have been found to be effective at penetrating lipid membranes. The use of tocotrienols for treating or preventing skin damage was disclosed in U.S. Pat. No. 5,545,398 to Perricone.
As a carrier of large quantities of carotenoids, tocopherols, and tocotrienols, palm oil is a desirable vehicle for the delivery of these vitamins to the skin. The use of palm oil in skin care formulations, however, has not been successful because palm oil has a very slow rate of crystallization, which continues even after processing. As a result of the continued crystallization, products containing palm oil products tend towards hardening and therefore, have a very short shelf-life. The problems associated with the crystallization of palm oil products is described in U.S. Pat. No. Re 30,086 to Carlile et al.